Go lambda hack

main.go

package main

import (
	"fmt"
)

// An interface can be implemented by a function type definition.
// This can be convenient for allowing inline function declarations
// of interfaces with only a single function.

// Example interface and function type definition:

type I interface {
	Func(x int) int
}

type IFunction func(x int) int

func (i IFunction) Func(x int) int {
	return i(x)
}

// Example usage:

func Something(x int, a I) int {
	return a.Func(x)
}

func main() {
	// The function must be cast to the function type, but this can be done inline.
	fmt.Printf("%v", Something(10, IFunction(func(x int) int { return x - 1 })))
}